Date calculator
Days until a date, days between dates, adding or subtracting days, and age. Everything is calculated inside this browser.
Days until
Days between dates
Add or subtract days
Age
How to use
- Pick the dates in the card you need. Start dates begin as today.
- Results update as soon as a date or number changes.
- For anniversaries counted with the first day as day 1, turn on "Count the start date as day 1" under Add or subtract days.
Questions
How is "days until" counted?
The target date minus the start date. The day before the target shows D-1, the day itself D-Day, the day after D+1.
Does "days between" include the start date?
The large number does not (the 1st to the 3rd is 2 days). The count with both ends included (3) is shown underneath.
How do I find a 100th-day anniversary?
If the first day counts as day 1, turn on "Count the start date as day 1" and enter 100. You get the date 99 days after the start.
How is age calculated?
Completed years: the difference between the years, minus one if the birthday has not yet come that year. People born on 29 February are counted a year older on 1 March in common years.
Can time zones or daylight saving shift the result by a day?
No. Only dates are used, never times of day, so neither affects the result. "Today" follows this device's clock.
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